UNIVERSITY OF CALIFORNIA ■ COLLEGE OF AGRICULTURE 
 
 AGRICULTURAL EXPERIMENT STATION 
 
 BERKELEY, CALIFORNIA 
 
 THE IMPORTANCE 
 
 OF CONTINUOUS GROWTH 
 
 IN BEEF CATTLE 
 
 H. R. GUILBERT, G. H. HART, K. A. WAGNON, and H. GOSS 
 
 Supplemental feeding on San Joaquin Experimental Range. 
 
 BULLETIN 688 
 
 September, 1944 
 
 UNIVERSITY OF CALIFORNIA ■ BERKELEY, CALIFORNIA 
 
CONTENTS 
 
 PAGE 
 
 Introduction 3 
 
 Eeview of literature 4 
 
 Experimental procedure 6 
 
 Eange area and forage 7 
 
 Animals used 9 
 
 Weights 9 
 
 Measurements 9 
 
 Photographs 10 
 
 Feeding 10 
 
 Marketing, slaughter, and carcass studies 12 
 
 Results 12 
 
 Discussion 26 
 
 General considerations 26 
 
 Growth and development 29 
 
 Carcass differences 29 
 
 Summary and conclusions 32 
 
 Literature cited 35 
 
THE IMPORTANCE OF CONTINUOUS GROWTH 
 
 IN BEEF CATTLE 2 
 
 H. R. GUILBEET, 3 G. H. HART, 4 K. A. WAGNON, 5 and H. GOSS 6 
 
 INTRODUCTION 
 
 According to a recent study (Guilbert, Fluharty, and Shepard, 1943 ), 7 72 
 per cent of California's 1942 beef production was derived from range forage, 
 field cleanup, and the hay production that is an integral part of the range- 
 cattle business. Beef cattle utilize and convert into human food the forage pro- 
 duction from an estimated 40 million acres of range lands, amounting to 40 
 per cent of the land area of the state. 
 
 A major problem, therefore, confronting beef -cattle producers is how best 
 to utilize the natural vegetation. The fallacy of expanding animal numbers 
 beyond feed supply has become generally recognized because of the difficult 
 problems arising from the war emergency. 
 
 The indices to guide operators are the pounds of beef produced per acre, 
 per animal unit, and per man hour, with due consideration for the condition 
 of the range and the well-being of the cattle. As suggested earlier (Wagnon, 
 Guilbert, and Hart, 1942), the concept of maximum forage utilization com- 
 patible with maximum production per animal unit might be widely applied in 
 defining the proper rates of stocking from both economic and ecological 
 standpoints. 
 
 Efficient meat production and efficient use of range feed involve supple- 
 mental feeds. These are supplied during the dry season to furnish specific 
 essential nutrients that become deficient in the natural vegetation. Thus a 
 plane of nutrition may be attained that will promote continuous growth and 
 development — a consideration especially important in young animals at the 
 time when the growth rate is potentially greatest and when live-weight gains 
 are most economical. These principles apply to animals that will be finished 
 on the range and to those that will be sold as feeders for feed-lot fattening. 
 They also apply to breeding herds maintained for high percentage calf crop, 
 adequate milk supply, and heavier weights of calves at weaning time. 
 
 If beef ranches are not producing 80 to 85 per cent calf crops, 450- to 500- 
 pound calves at weaning, and 800- to 850-pound steers at yearling age, pro- 
 duction efficiency can usually be improved by changes in management and 
 feeding practices. 
 
 The data presented cover paired animals fed approximately equal quantities 
 of supplemental feed and carried to approximately equal finish, but fed at 
 
 1 Eeceived for publication March 23, 1944. 
 
 2 This report is part of a project on range livestock management in the granite area of the 
 Sierra foothills. Cooperators in the project are the California Forest and Range Experiment 
 Station, U. S. Forest Service, and the Division of Animal Husbandry, College of Agriculture, 
 University of California. 
 
 3 Associate Professor of Animal Husbandry and Associate Animal Husbandman in the 
 Experiment Station. 
 
 4 Professor of Animal Husbandry and Animal Husbandman in the Experiment Station. 
 
 5 Assistant in Animal Husbandry. 
 
 8 Professor of Animal Husbandry and Animal Husbandman in the Experiment Station. 
 7 See "Literature Cited" for complete data on citations, which are referred to in the text 
 by author and date of publication. r o -i 
 
4 University of California — Experiment Station 
 
 different times so that the growth curves are widely different. The results 
 show strikingly how one can meet problems of production efficiency eco- 
 nomically by using supplemental feeds in limited quantities when they are 
 most needed and best utilized by the animals. 
 
 REVIEW OF LITERATURE 
 
 Space would not permit complete citation of work having a bearing on the 
 present experiment. All experiments on nutrition and production show that 
 with animals, as with machines, factories, or other working units, production 
 is most efficient when operation is proceeding at a rate that approaches full 
 capacity. In the dairy cow or the meat animal, the feed requirement for body 
 maintenance and temperature regulation represents a large part of total feed 
 use. The greater the rate of production (within certain limits) that can be 
 obtained by liberal feeding, the greater is the efficiency from the standpoint 
 of pounds of feed required per pound of resulting product. This may be re- 
 ferred to as biological efficiency. Economic efficiency depends upon relative 
 costs of different phases of production — for example, cost of summer gain on 
 range compared with winter gain on hay or concentrate supplements. These 
 considerations modify the degree of approach to the ideal that may be made 
 under any specific situation. Maintenance for short periods may, in some cases, 
 be justified (Black, Quesenberry, and Baker, 1939) . In general, however, very 
 close correlation is found between biological efficiency and economic efficiency 
 as represented by returns in dollars and cents, especially when one takes the 
 broader viewpoint of the lifetime history and performance of the animals. 
 
 An extensive fundamental study on the effect of nutritional plane and age 
 on efficiency of feed utilization, development, and composition of the body 
 and the carcass was outlined by Waters and carried out by Trowbridge, 
 Moulton, and Haigh (1915, 1918, 1919; Moulton, Trowbridge, and Haigh, 
 1921, 1922a, 1922&). In this work at the Missouri Agricultural Experiment 
 Station, higher planes of nutrition proved to be more efficient from the stand- 
 point of energy recovery and of the recovery of edible meat ; undernutrition, 
 resulting in a slow rate of gain, affected the height growth least, the length 
 growth and width at hips to a greater extent ; hindquarter development was 
 retarded more than f orequarter by undernutrition and stimulated most by a 
 high plane of nutrition. Marked differences, of course, developed in percent- 
 age of bone, fat, and lean in the carcasses as a result of different planes of 
 nutrition. Some animals were continued on experiment over a period of three 
 to four years. In these experiments the ration was composed of alfalfa hay, 
 grain, and linseed meal and presumably was nutritionally complete. The 
 total daily allowance, however, was varied to secure the different growth rates 
 desired. 
 
 Watson (1943) at University College, London, seeking information basic 
 to wartime food-production policy in England, evaluated the Missouri data 
 thoroughly. He desired to establish the mathematical relations of nutritional 
 plane, age, and weight to efficiency of production. His analysis further em- 
 phasizes the physiological efficiency of high nutritional planes. Doubling the 
 food intake over maintenance was shown to increase efficiency 4.8 times. Ac- 
 cording to Watson's calculations, full-feeding to a weight of 840 pounds live 
 
[Bul. 688] Importance of Continuous Growth in Beef Cattle 
 
 weight with a carcass fat content of about 22 per cent and a carcass yield of 
 60 per cent gave highest efficiency if protein return was the sole consideration. 
 Considered on an energy basis alone, a live weight of 1,700 pounds, together 
 with 35 per cent fat in the carcass and a yield of 64 per cent, was most efficient. 
 If both fat and protein were considered in relation to the value indicated by 
 popular preference, then 1,150-pound animals dressing out about 59 per cent 
 had highest efficiency — a weight and yield consistent with common market 
 practice. 
 
 Hammond and his co-workers at Cambridge University, England, have 
 attacked in the broadest and most basic manner the problem of efficient pro- 
 duction of high-quality carcasses. These workers have covered both wild and 
 domestic species in studies of growth and development. They particularly 
 
 200 
 
 1 L_J I I I 
 
 300c/oc/s 
 A/// 
 
 0/r//i 4 0/2/6 20 24 28 32 36 40 
 
 Age - n/eeAs 
 
 Fig. 1. — Plan of McMeekan's (1940-1941) experiment with swine. 
 
 considered, for various parts of the body, the differential growth rates that 
 occur between birth and maturity and result in the difference in body shape 
 of young and adults. Hammond's many years of carcass measurements at the 
 Smithfield Show in London have been coupled with studies of British breeding 
 data. His lifetime investigations of the physiology of reproduction and growth, 
 in which he has followed in the footsteps of two distinguished predecessors, 
 Marshall and Heape, make the Cambridge group the chief center of thought 
 in these subjects. 
 
 McMeekan's (1940-1941) recent classic work with swine, in Hammond's 
 laboratory, substantiated and extended the previous work of Verges (1936) 
 with sheep, showing how variations in shape of the growth curve affect the 
 relative development of parts and the composition of the carcass. This work 
 demonstrated that (within limits) one could obtain the desired carcass charac- 
 teristics either by imposing a nutritional environment in the necessary direc- 
 tion or by changing the strain or breed to an earlier- or later-maturing type. 
 
 Figure 1 illustrates the plan of McMeekan's experiments with swine. Litter 
 mates from an inbred strain were selected to minimize genetic variation in 
 the experimental animals. One group, designated as "high-high," was kept 
 
6 
 
 University of California — Experiment Station 
 
 on a high plane of nutrition until the animals reached a slaughter weight of 
 200 pounds at 180 days of age. A second group, designated as "low-low," was 
 continued on a limited ration and attained 200 pounds weight in 300 days. The 
 plane of nutrition of the other two groups, high-low and low-high, was so 
 regulated that they both reached 200 pounds at 240 days of age, but by differ- 
 ent routes. Table 1 shows the differences in carcass composition. The high-high 
 group made the best butcher hogs ; the high-low the best bacon carcasses. The 
 low-high group, though it weighed as much at the same age as the litter mates 
 in the high-low group, had an excessive amount of fat in relation to develop- 
 ment of muscle. This group had the characteristics of an early-maturing lard 
 type, as compared with the bacon type in the high-low group. The group kept 
 
 TABLE 1 
 
 Variation in Percentage Composition of Carcass Depending 
 
 on the Shape of the Growth Curve 
 
 (McMeekan, 1940-1941) 
 
 Group 
 
 High-high 
 Low-low . . 
 High-low. 
 Low-high . 
 
 Live weight, 
 pounds 
 
 200 
 200 
 200 
 200 
 
 Percentage composition of carcass 
 
 Bone 
 
 11 
 12 
 11 
 10 
 
 Muscle 
 
 40 
 49 
 45 
 36 
 
 Fat 
 
 38 
 27 
 33 
 44 
 
 on a low plane of nutrition were long and lean of body; had too high a propor- 
 tion of legs, head, and neck; showed poor development of loin and hind- 
 quarter; and yielded carcasses deficient in fat, Detailed study of the per- 
 centage increase in individual bones, muscles, and fat tissue throughout the 
 body demonstrated that in undernutrition the length growth of bones takes 
 priority, for nutrients available, over thickness growth; early-maturing parts 
 (long bones, head, neck, and forequarter) over late-maturing parts such as 
 loin and hindquarter ; muscle growth over fat deposition. At 16 weeks of age, 
 for example, the weight of the loin in the high-plane pigs was 450 per cent that 
 in the low plane, and the head was 209 per cent. Similarly the weight of the 
 fat in the high-plane pigs was 1007 per cent that of the low plane, while bone 
 was only 224 per cent. Thus those tissues and parts that develop later in life 
 (such as loin and fat) are stimulated by a rapid rise in the weight-growth 
 curve, whereas the proportion of earlier-maturing parts (such as head and 
 bone) is accentuated by a slow rise of the weight curve. 
 
 EXPERIMENTAL PROCEDURE 
 
 The Missouri experiments were involved with variations in plane of nutri- 
 tion, each plane remaining more or less constant for definite periods. In 
 McMeekan's work, final weight was the constant factor. The present experi- 
 ment was an attempt to follow, with modifications, the pattern of McMeekan's 
 high-high and low-high groups under the environmental conditions of the 
 San Joaquin Experimental Range. This experiment differed in that the high 
 group was fed for continuous but not maximum gain, time was equal for both 
 
[BrL. 688] Importance of Continuous Growth in Beef Cattle 7 
 
 groups, and approximately equal fatness was attained at different average 
 final weights. Since desirable market weight is less sharply defined for cattle 
 than for swine and sheep, perhaps equality of finish may be a more practical 
 constant to require in some types of cattle experiments. 
 
 Range Area and Forage. — The San Joaquin Experimental Range is located 
 in the so-called granite area of the Sierra Nevada foothills at an elevation of 
 1,000 to 1,500 feet. The area is characterized by scattered oak and Digger pine 
 trees and brush, with a ground cover consisting largely of annual grasses and 
 herbs. The soil, derived from decomposed granite, is shallow except in swales, 
 
 100 
 90 
 60 
 70 
 
 K 60 
 <o 50 
 
 it' 
 
 40- 
 
 30 
 20 
 10 
 
 ^ 
 
 GREEN FORAGE 
 
 I 
 \ 
 
 V \ 
 
 4-' 
 
 I 
 / 
 I 
 J 
 
 .o e< 
 
 \ 
 
 I 
 
 I 
 
 | T.O.N. IN 
 
 > 1 DRY MATTER 
 
 c«- L,o— o^.. 
 
 — - o — o -~e_ <j_ o— c 
 
 — °' 
 
 DIGESTIBLE 
 PROTEIN 
 
 ■j* 
 
 / 
 
 JAN. FEB. MAR. APR. MAY JUNE JULY AUG. 6ER OCT. NOV. DEC 
 
 Fig. 2. — Typical seasonal changes in total digestible nutrients and digestible protein in 
 dry matter of the forage as grazed on the San Joaquin Experimental Bange, together with 
 an estimate of percentage of green forage consumed. 
 
 which constitute a small part of the total area. Rock outcroppings are numer- 
 ous. The area, the environmental conditions, the forage, and the organization 
 of investigational work are described in detail by Hutchison and Kotok (1942) . 
 
 The annual grasses and herbs germinate quickly after the first rains, usually 
 in November. Because of low temperature, growth is slow until February. 
 A short period of rapid forage development in March and April is followed by 
 maturing and drying in May and June. The time of forage drying depends on 
 late spring rains and varies from year to year. Swale areas normally remain 
 green into June, and nearly all the forage is completely dry by the first of 
 July. Small quantities of Spanish clover or other late-growing species remain 
 green for a longer period, but are quickly utilized by grazing. 
 
 Figure 2 illustrates the typical seasonal changes in the range forage. The 
 curves are based upon chemical analyses of forage samples composited over 
 
8 
 
 University of California — Experiment Station 
 
 2-week periods throughout the year and collected, to represent actual grazing, 
 by following the cattle. Digestibility is based upon digestion trials with similar 
 green forage, together with digestion trials on samples of the dry grass, 
 
 TABLE 2 
 
 Pairing of Animals on the Basis of Age, Sire, Grade, and Weights 
 
 from January to July, 1941 
 (The first animal of each pair was placed in group 1 ; the second in group 2) 
 
 Pair and 
 
 Weight in pounds 
 
 Age, 
 days 
 
 Sire 
 no. 
 
 Feeder 
 
 animal nos. 
 
 Jan. 31 
 
 April 2 
 
 June 9 
 
 July 3 
 
 grade* 
 
 Pair 1 : 
 
 
 
 
 
 
 
 
 02 
 
 102 
 120 
 
 225 
 235 
 
 380 
 370 
 
 400 
 390 
 
 176 
 183 
 
 635 
 635 
 
 2- 
 
 09 
 
 2— 
 
 Pair 2: 
 
 
 03 
 
 167 
 179 
 
 290 
 300 
 
 420 
 420 
 
 454 
 460 
 
 253 
 240 
 
 604 
 604 
 
 2 
 
 013 
 
 2 
 
 Pair 3: 
 
 
 04 
 
 179 
 205 
 
 330 
 340 
 
 500 
 
 485 
 
 531 
 520 
 
 270 
 256 
 
 604 
 604 
 
 2- 
 
 012 
 
 2- 
 
 Pair 4: 
 
 
 08 
 
 159 
 
 300 
 
 465 
 
 490 
 
 239 
 
 604 
 
 2 
 
 010 
 
 173 
 
 300 
 
 435 
 
 475 
 
 228 
 
 604 
 
 2 
 
 Pair 5: 
 
 
 014 
 
 112 
 123 
 
 230 
 244 
 
 390 
 395 
 
 420 
 420 
 
 209 
 210 
 
 628 
 635 
 
 2- 
 
 016 
 
 2— 
 
 Pair 6: 
 
 
 027 
 
 240 
 
 340 
 
 490 
 
 525 
 
 267 
 
 533 
 
 2 
 
 032 
 
 248 
 
 380 
 
 520 
 
 545 
 
 257 
 
 533 
 
 2- 
 
 Pair 7: 
 
 
 
 
 
 
 
 
 028 
 
 200 
 197 
 
 335 
 340 
 
 480 
 495 
 
 525 
 525 
 
 214 
 226 
 
 647 
 635 
 
 2- 
 
 05 
 
 2- 
 
 Pair 8: 
 
 
 
 
 
 
 
 
 035 
 
 213 
 
 350 
 
 480 
 
 520 
 
 265 
 
 533 
 
 2 
 
 036 
 
 217 
 
 325 
 
 480 
 
 510 
 
 254 
 
 533 
 
 2 
 
 
 
 Group 1, average 
 
 172 
 
 300 
 
 451 
 
 483 
 
 237 
 
 
 
 Group 2, average 
 
 183 
 
 308 
 
 450 
 
 481 
 
 232 
 
 
 
 * Grade 2 corresponds to U.S. "average choice"; grade 2— to "low choice." 
 
 Spanish clover, and dry filaree. Other points were derived from the relation 
 of lignin content to digestibility. 8 These data are for 1937 — a favorable year 
 in which there was considerable growth of clovers in the swales and in which 
 late rains promoted the late-growing species. 
 
 Except for drying of the forage at an earlier date in some years, the data in 
 figure 2 illustrate the typical nutritive regimen to which the cattle are regu- 
 larly subjected. When green forage appears it is consumed along with the old 
 crop in increasing amounts, as shown by the green-forage curve. Protein and 
 
 8 Unpublished data of H. Goss and H. It. Guilbert. 
 
[Bul. 688] Importance of Continuous Growth in Beef Cattle 9 
 
 total digestible nutrients reach a peak at the height of the growing season and 
 decline as the forage matures. The young green forage alone is more highly 
 digestible than the curves indicate. The trend is modified by the amount of old 
 forage taken with the new. Digestible protein, based on correction of apparent 
 digestibility for metabolic nitrogen (Guilbert and Goss, 1944), declines to 
 between 1 and 2 per cent. The slight rise in August was caused by selective 
 grazing by the animals, which were transferred to the previously ungrazed 
 dry forage containing some of the late-growing green plants and dried 
 legumes. 
 
 As shown by Wagnon, Guilbert, and Hart (1942), phosphorus declines with 
 the protein to levels of 0.10 to 0.20 per cent of the dry matter. The protein 
 deficiency during the years thus far studied has apparently been more acute 
 than the phosphorus, since no clinical symptoms of phosphorus deficiency such 
 as significantly lowered blood phosphate have been noted in unsupplemented 
 animals. Calcium content of the herbage is adequate throughout the year. The 
 total digestible nutrients in the dry forage before it is leached by autumn 
 rains are sufficient to permit slow weight gain when protein deficiency is al- 
 leviated by protein concentrates that also supply sufficient phosphorus. Pre- 
 viously obtained data (Wagnon, Guilbert, and Hart, 1942) had shown that 
 without supplements all classes of cattle lost weight soon after the first of 
 July, regardless of the abundance of feed. 
 
 Animals Used. — Sixteen steer calves were selected at weaning time (July 1, 
 1941) from the Hereford herd on the Experimental Range. They were divided 
 into eight pairs matched as closely as possible for age, weight, consistency of 
 previous gains, sire, grade, and body measurements. Table 2 shows weights, 
 age, sire, and grade of each pair. 
 
 The sire was the same for paired animals, except that in pairs 5 and 7 the 
 sires were half brothers of comparable grade and quality. 
 
 Weights. — Because of the general impracticability of taking three con- 
 secutive daily weights under pasture and range conditions, a single weight 
 was taken at intervals of 25 to 35 days. The initial weight was recorded soon 
 after separation of the calves from their mothers. For subsequent weighing, 
 including May 11, 1942, the animals were driven from near-by pastures to 
 the corrals and weighed full between 8 :00 and 9 :00 a.m. On and after June 12, 
 weights were taken between 6 :00 and 7 :00 a.m. after the animals had stood 
 about 12 hours in a corral without feed or water. 
 
 In earlier studies, 9 fill (determined by the amount of shrink in 12 hours) 
 increased with forage development to a maximum in May or June, but de- 
 clined thereafter as the feed dried, became nutritionally deficient, and was 
 rendered relatively unpalatable. Thus gains were exaggerated in the period of 
 increasing fill and minimized (or the losses exaggerated) in the period of de- 
 creasing fill. Shrunk weights reduced this systematic error and gave a truer 
 picture of body -weight changes. 
 
 Measurements. — At each weighing time the following measurements were 
 taken : height at withers, height at hook bones, heart girth, horizontal length 
 from point of shoulder to a line dropped vertically from the pinbones, length 
 of head at the eye level, and round measurement. This last measurement, pro- 
 
 9 Unpublished data of K. A. Wagnon and H. R. Guilbert. 
 
10 
 
 University of California — Experiment Station 
 
 posed by Gregory (1933), extends horizontally from the point of the stifle 
 (patella) on one side around the thighs to the point of the stifle on the opposite 
 side. The animals were measured in a squeeze-type chute. They soon became 
 gentle (with one exception, no. 012) ; little difficulty was encountered in secur- 
 ing normal stance and satisfactory measurements. Previous culling of the wild 
 cows, together with careful handling of the cattle, had resulted in a remark- 
 ably tractable herd. 
 
 Photographs. — A photographic chute was constructed as illustrated in fig- 
 ure 3. Photographs were taken at each weighing time both on black-and-white 
 and on color film. The latter was used for lantern slides and for checking or 
 securing additional measurements when projected at one third life size. The 
 
 Fig. 3. — Chute used to photograph animals. The grid wires are spaced 
 
 15 centimeters apart. 
 
 cross wires of the chute were spaced 15 centimeters apart. The cameras were 
 set up each time on the same spot, on a line intersecting at right angles the 
 center of the chute, and at a distance of 8 meters (about 26 feet). After the 
 first animal had been photographed, it was held immediately in front of the 
 photographic chute, and its presence tended to alleviate any nervousness in 
 the animal being photographed. Animal 012 (whose mother was wild) never 
 became quiet ; after he had twice broken the cross wires, the attempt to photo- 
 graph him was abandoned. The remainder of the steers gave little trouble 
 after the first time, and it was comparatively easy to secure a pose that was 
 normal. 
 
 Feeding. — After being separated from their dams, the steers of both groups 
 were held in corrals for a few days until they were weaned. During this time 
 they were taught to eat rolled barley and a cottonseed cake that was 43 per 
 cent protein. Next, the groups were separated and placed in adjacent 90-acre 
 pastures furnishing comparable amounts and quality of dried feed, which 
 had not been subjected to grazing during the growing season. Group 1 was 
 fed supplements for the purpose of producing daily gains of 1.00 to 1.25 
 pounds until January 1, 1942 (period I). Group 2 received no supplements 
 
[Bul. 688] Importance of Continuous Growth in Beef Cattle 
 
 11 
 
 during this time and lost weight. Supplements were then given to group 
 2; and group 1 was allowed to rely on forage alone, which at this time con- 
 sisted of a mixture of old forage and new green growth. Group 2 ate supple- 
 ments readily during the early part of period II, while green forage was short 
 and high in moisture. Consumption declined, however, as the forage im- 
 
 //oo 
 
 Averages. 
 
 Oroi/p/j 
 
 /30 
 
 — • 6roi/p 2 
 
 /oo 
 
 90 
 
 SO 
 
 70 
 
 
 
 Poc//?d /neGss/re/nefifj 
 
 cm 
 
 
 
 
 
 II ill 1 1 
 
 'i 
 
 1 ' 
 
 de/g/?f af tv/ f tiers f cm 
 
 /SO 
 
 - Le/iy/ti, stioc//der-p//7p'orte J cm 
 
 MO 
 
 IsZ. 
 
 /30 
 
 
 /20 
 
 J**"^ 
 
 * 
 
 //0 I 
 
 
 
 /OO 
 
 i . ill i i 
 
 1 1 ' 
 
 SO 
 
 48 
 
 46 
 
 44 
 
 42 
 
 40 
 
 38 
 
 
 
 22 
 
 20 
 
 dead /enyftij cm 
 
 ■ deod w/df/i, cm 
 
 30 /OO /30 200 230 300 350 400 430 
 
 ///77<? //? days 
 
 ■—I 
 
 L 
 
 Per/od I 
 
 £ 
 
 m- 
 
 30 /OO /50 200 250 300 350 400 450 
 
 LT/me /n do//s 
 
 Per/od I 
 
 E 
 
 Vm-A 
 
 Fig. 4. — Average growth curves of groups 1 and 2. 
 
 proved. Feed intake again increased with maturing and drying of the forage. 
 In period III, extending from June 13 to September 7, 1942, both groups were 
 full-fed concentrates in the pastures at the rate of approximately 1 pound for 
 each 100 pounds of live weight. The steers were fed in troughs conveniently 
 located and were trained to come to feed when called. (See frontispiece.) 
 Except for the last 30 days, when twice-daily feeding was employed and the 
 amount increased to 1.5 pounds per 100 pounds live weight, the concentrates 
 were given once daily. When a heavy concentrate ration is fed in a single feed 
 during hot weather, evening feeding was practiced, on the theory that the 
 
12 University of California — Experiment Station 
 
 resultant peak of body heat production might more readily be dissipated dur- 
 ing the cooler nights than during the heat of the day. Empirical observations 
 appear to justify this practice. 
 
 Table 3 gives the details of feeding throughout the experiment. 
 
 Marketing, Slaughter, and Carcass Studies. — The steers were brought from 
 their pastures to the corrals and weighed just before being loaded on the truck 
 at 3 :00 p.m., September 14. They arrived in the South San Francisco Union 
 Stock Yards at 3 :00 a.m., September 15. They were allowed feed and water ; 
 were sold and weighed about 10 :00 a.m. of that day. They were purchased by 
 Swift and Company, the buyer having attempted to evaluate the individual 
 animals as closely as possible. They were slaughtered on September 17, the 
 carcasses individually identified, and the warm dressed weights obtained. The 
 carcasses, graded and stamped by official graders, were purchased by the 
 Safeway Stores and were transferred to their aging and distributing plant 
 on September 21. On September 24 the carcasses were weighed, the left sides 
 were cut into wholesale cute, and each cut was weighed. The cutting was done 
 by a Safeway crew. All the ribs were left on the forequarter. The cuts were 
 whole round including rump, whole loin including flank, prime rib, shin and 
 shoulder (shoulder removed at the joint and including the cross arm cuts), 
 chuck including neck, and long plate including plate and brisket. After cutting 
 and weighing of the individual wholesale cuts, a sample consisting of the 12th 
 and 13th rib cuts was taken from each carcass. These rib cuts were brought to 
 Davis, the edible portions separated from the bone, and weights obtained on 
 meat and bone. The fat and lean from each rib cut were run twice through a 
 grinder and thoroughly mixed ; and a sample was taken for analysis of fat 
 and water content. 
 
 RESULTS 
 
 Figure 4 presents the average growth curves of each group in terms of live 
 weight, heart girth, height at withers, length of body, round measurement, and 
 head length and width. Plates 1 to 7 inclusive are photographs of each pair of 
 steers, except nos. 04 and 012, taken 5 weeks after the beginning and at the end 
 of period I and at the close of the experiment. Figures 5 to 8 inclusive show 
 the same measurements as figure 4, except those on the head, for each pair of 
 steers. Some of the more important group-average data appear in table 4. 
 Table 5 shows in detail the carcass data and the percentage of lean, fat, and 
 bone in the rib cuts. In tables 4 and 5, where the difference between group 
 averages of basic data are statistically significant the figures are printed in 
 italics. 10 Table 6 compares the live and carcass grades and individual live- 
 weight prices with data on percentage fat in the rib cut and on carcass-value 
 variation due to grade and conformation. 
 
 10 Statistical analysis of the data was made by Dr. G. A. Baker, Junior Statistician in the 
 
 Experiment Station. Probability, P, for difference between various items was as follows: 
 
 P 
 final weight 0.01; carcass weight 0.06, 5- = 0.03; final heart girth, height, length (shown 
 
 P 
 
 in fig. 4) 0.06 — = 0.03; percentage fore and hindquarter, 0.05. The statistician felt justi- 
 fied in considering the items where «c is shown as significant, since they were highly cor- 
 related with characteristics such as final weight that were highly significant. Other differ- 
 ences may be real, but there are insufficient data for decisive demonstration. 
 
[Bul. 688] Importance of Continuous Growth in Beef Cattle 
 
 Po/rl. ^—+No.OZ, -—A/o.09 Pair 2. t >-—^No.03 J °~~°No.0/3 
 
 13 
 
 /ie/g/?f af tv/f tiers 
 
 ^^Z^'^ 1 
 
 1 1 1 1 1 1 1 1 1 1 - 
 
 O 50 /OO /50 200 250 300 350 400 450 O 50 /OO /50 200 250 300 350 4O0 450 
 
 V 
 
 Time m dot/s 
 Period 7 '-+— E — 
 
 -EL -A L- 
 
 Ti/ne m days 
 Period I -^r— E »1« EL —I 
 
 Fig. 5. — Individual growth curves: pair 1, animals 02 (group 1) and 09 (group 2) ; pair 2, 
 
 animals 03 (group 1) and 013 (group 2). 
 
14 
 
 University of California — Experiment Station 
 Po/r3. • — *M).04 t —-«MoO/2 Pair 4. <~^>A/o 08, °~--°A/oO/0 
 
 § 
 
 /zo 
 //o 
 
 /OOh, 
 
 90 
 O 
 
 Hey/it 
 
 &f tv/f/iers 
 
 _!__ 
 
 
 
 ._..o— - * 
 
 1 
 
 r 
 
 i 
 
 .«r-° 
 
 1 1 
 
 ill 1 1 
 
 i, 
 
 1 ' 
 
 tfe/y/if a/ w/f tiers 
 
 § 
 
 Lengf/i, sfiov/der-p/fibo/ie 
 
 O SO /OO /50 200 260 300 350 400 450 
 
 T/rie //i days 
 
 u 
 
 Period f 
 
 E 
 
 M- 
 
 O SO /OO /SO 200 250 300 3 SO 400 450 
 
 r//i?e //7 days 
 
 Period I ^r— IT 
 
 ■m 
 
 j 
 
 Fig. 6. — Individual growth curves: pair 3, animals 04 (group 1) and 012 (group 2) ; pair 4, 
 
 animals 08 (group 1) and 010 (group 2). 
 
PLATES 
 
NO. 02. GROUP 1 
 
 NO. 09. GROUP 2 
 
 30 60 90 /20 /SO /SO 2/0 O 30 60 90 /20 /50 00 2/0 
 
 Ceflffmefers 
 
 Plate 1. — Pair 1, animals 02 (group 1) and 09 (group 2). Top, photograph 
 taken 5 weeks after the experiment began ; middle, at the end of period I ; 
 bottom, at the end of the experiment. 
 
 Carcass of no. 02: grade, low good; yield, 58.4 per cent. No. 09: grade, com- 
 mercial; yield, 55.9 per cent. 
 
 [16] 
 
NO. 03. GROUP 1 
 
 NO. 013. GROUP 2 
 
 30 60 90 /20 /50 /80 2/0 30 60 90 /20 /50 /do 2/0 
 
 Ce/?fffffefer$ 
 
 Plate 2. — Pair 2, animals 03 (group 1) and 013 (group 2). Top, photograph 
 taken 5 weeks after the experiment began; middle, at the end of period Ij 
 bottom, at the end of the experiment. 
 
 Carcass of no. 03: grade, top good; yield, 60.9 per cent. No. 013: grade, 
 good; yield, 60.4 per cent. 
 
 [17] 
 
NO. 08. GROUP 1 
 
 NO. 010. GROUP 2 
 
 90 /20 /50 /80 2/0 
 
 '20 /50 /80 Z/O 
 
 Ce/?f//r?efers 
 
 Plate 3. — Pair 4, animals 08 (group 1) and 010 (group 2). Top, photograph 
 taken 5 weeks after the experiment began; middle, at the end of period I; 
 bottom, at the end of the experiment. 
 
 Carcass of no. 08: grade, good; yield, 58.7 per cent. No. 010: grade, com- 
 mercial; yield, 59.9 per cent. 
 
 Lis] 
 
NO. 014. GROUP 1 
 
 NO. 016. GROUP 2 
 
 J<? ft? P<7 /a? /.#? #<? ^/<7 O 30 60 90 /20 /30 /80 2/0 
 
 Ce/?f//7?efers 
 
 Plate 4. — Pair 5, animals 014 (group 1) and 016 (group 2). Top, photograph 
 taken 5 weeks after the experiment began; middle, at the end of period I; 
 bottom, at the end of the experiment. 
 
 Carcass of no. 014: grade, commercial; yield, 58.2 per cent. No. 016: grade, 
 commercial; yield, 58.7 per cent. At time of slaughter, these animals were on 
 the borderline between good and commercial grades. 
 
 [19] 
 
NO. 027. GROUP 1 
 
 NO. 032. GROUP 2 
 
 O 30 60 90 /20 /SO /80 2/0 
 
 30 60 90 /20 /50 /SO 3/0 
 
 Ce/?f//77efers 
 
 Plate 5. — Pair 6, animals 027 (group 1) and 032 (group 2). Top, photograph 
 taken 5 weeks after the experiment began ; middle, at the end of period I ; 
 bottom, at the end of the experiment. 
 
 Carcass of no. 027: grade, good; yield, 59.4 per cent. No. 032: grade, good; 
 yield, 62.2 per cent. 
 
 [20] 
 
NO. 028. GROUP 1 
 
 NO. 05. GROUP 2 
 
 in 
 m 
 
 -'t*TH^„ : W^lb, . -MB! IB 
 
 lit; naniM i 
 
 .&? 5(7 Ptf /20 /50 /SO 2/0 
 
 JO 60 90 /20 /50 /80 2/0 
 
 Cenf/mefers 
 
 Plate 6. — Pair 7, animals 028 (group 1) and 05 (group 2). Top, photograph 
 taken 5 weeks after the experiment began; middle, at the end of period I; 
 bottom, at the end of the experiment. 
 
 Carcass of no. 028: grade, good; yield, 58.5 per cent. No. 05: grade, good; 
 yield, 60.5 per cent. 
 
 [21] 
 
NO. 035. GROUP 1 
 
 NO. 036. GROUP 2 
 
 60 90 /20 /50 /80 2/0 
 
 '50 /80 
 
 Cenfi/nefers 
 
 Plate 7. — Pair 8, animals 035 (group 1) and 036 (group 2). Top, photograph 
 taken 5 weeks after the experiment began; middle, at the end of period Ij 
 bottom, at the end of the experiment. 
 
 Carcass of no. 035 : grade, commercial ; yield, 59.3 per cent. This animal, as 
 shown above, had the appearance of a good-grade slaughter steer ; but distribu- 
 tion of fat covering over the round and inside the ribs apparently was inade- 
 quate in the opinion of the grader. No. 036 : grade, good ; yield, 60.3 per cent. 
 
 [22] 
 
[Bul. 688 J Importance op Continuous Growth in Beef Cattle 
 
 Pa/r 5. « — ^ A/a 0/4, —•- A/a 0/6 Po/r 6. ■ — * A/a 027, ~~* A/a 032 
 
 23 
 
 Pov/id /nees/sre/T/e/?/ 
 
 Pai//?d /7?e/7s//re/7?e/?/ L,— <** 
 
 V-o— o-- 
 
 f-o-' 
 
 1 1 ill 1 1 'l 17 
 
 //e/gr/?/ &/ iv///?ers 
 
 /so - Le/?g//?, s/?ot//c/er-/>/rt/>or?e 
 
 I 
 
 J t 
 
 Le/?g//? t s/?o///c/er-/>/noo/?e 
 
 O SO /OO /SO 200 250 JOO S50 400 450 SO /OO /SO 200 2 SO SOO S50 400 4SO 
 
 7/ me //? c/a//s 
 
 T///7e //? days 
 V Period '1 '-4— H — 
 
 m- 
 
 *- Period ' I 
 
 £■ 
 
 ~m-A 
 
 Fig. 7. — Individual growth curves: pair 5, animals 014 (group 1) and 016 (group 2) ; pair 6 
 
 animals 027 (group 1) and 032 (group 2). 
 
24 
 
 University of California — Experiment Station 
 Pair 7. •— tfo.028 t -~- No. 05 Pair 8. «>— * flo.035,—— A/o.036 
 
 Live tve/gtif 
 
 He/gtif #f tv /'/tiers 
 
 j j t 
 
 He/ah f af wi /tiers 
 
 /so - Leog/ti, stioc//der-p//76o/?e 
 /40 - 
 
 'Lergfti, stiou/der-p/rtbone 
 
 O SO /OO /SO 200 250 3O0 350 400 45 O O SO /OO /50 200 25 O 300 350 400 4S0 
 
 T///7S //? days P/d?e /ti days 
 
 •I* — H — X+-M-A U/ 
 
 *— Period I • 
 
 -Period I- 
 
 PT 
 
 -4—M-M 
 
 Fig. 8. — Individual growth curves: pair 7, animals 028 (group 1) and 05 (group 2) ; pair 8, 
 
 animals 035 (group 1) and 036 (group 2). 
 
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26 
 
 University of California — Experiment Station 
 
 DISCUSSION 
 
 General Considerations. — From the viewpoint of practical operators, the 
 most striking result shown in table 4 is that group 1, fed for continuous growth 
 and development, made 106 pounds more gain and 108 pounds greater final 
 weight, while the total supplemental feed consumption was only 70 pounds 
 
 TABLE 4 
 
 Summary of Feeding Trial and Slaughter Data 
 (Average of eight animals in each group) * 
 
 Weight, pounds: 
 
 July, 1941 
 
 January, 1942 
 
 June, 1942 
 
 September, 1942 
 
 Total gain, pounds 
 
 Total concentrates fed, pounds 
 
 Feed cost at 2 cents per pound .... 
 
 Shipping weight, pounds 
 
 Selling weight, pounds 
 
 Shrink in marketing, per cent 
 
 Shrink in cooler, per cent 
 
 Cold carcass weight, pounds 
 
 Percentage yield of dressed carcass 
 Selling price per hundred pounds. 
 
 Selling price per steer 
 
 Hindquarters, per cent of carcass . 
 Forequarters, per cent of carcass. . 
 
 Bone in rib cut, per cent 
 
 Fat in rib cut, per cent 
 
 Lean in rib cut, per cent 
 
 Lean in fat-free cut, per cent 
 
 Carcasses, good grade 
 
 Carcasses, commercial grade 
 
 Yields of wholesale cuts 
 
 Group 1 
 
 Group 2 
 
 483 
 
 481 
 
 678 
 
 461 
 
 860 
 
 765 
 
 1,012 
 
 904 
 
 529 
 
 423 
 
 1,738 
 
 1,668 
 
 $34 76 
 
 $33.36 
 
 1,086 
 
 923 
 
 969 
 
 868 
 
 6.4 
 
 5.9 
 
 1.65 
 
 1 44 
 
 573 
 
 521 
 
 59.1 
 
 60.0 
 
 $13 88 
 
 $13.48 
 
 $134.56 
 
 $117.05 
 
 48.3 
 
 47 5 
 
 51.7 
 
 52.5 
 
 14.9 
 
 15.4 
 
 32.7 
 
 30.9 
 
 52.4 
 
 53.7 
 
 77.9 
 
 77.8 
 
 5 
 
 4 
 
 3 
 
 4 
 
 $127.79 
 
 $115.02 
 
 * Italics indicate that the differences between group averages of basic data are statistically significant. 
 
 greater. By reason of the greater weight and average selling price, group 1 
 (under the cost and price relations obtaining at the time of the experiment) 
 returned $17.51 more per head, though the difference in supplemental feed 
 cost was only $1.40. 
 
 In June, 1942, when both groups might have been sold as feeders, group 1 
 weighed an average of 860 pounds, and group 2 weighed 765 pounds — a differ- 
 ence of 95 pounds. At this time group 1 had consumed 41 pounds less total 
 feed than group 2 (716 pounds compared with 757 pounds). From 40 to 50 
 days in the feed lot would have been necessary to make up for this difference 
 of 95 pounds in weight between the average of the groups. According to aver- 
 age feed-lot records, the feed required would have been about 400 to 450 
 pounds each of concentrates and harvested roughage. 
 
 The difference in efficiency can be attributed largely to the comparatively 
 small daily allowance of supplement, which permitted productive utilization 
 of the otherwise nutritionally deficient dry forage and reduced the proportion 
 of total feed used for maintenance. 
 
[Bul. oss J Importance of Continuous Growth in Beef Cattle 27 
 
 Xo means were available for ascertaining the amount of range forage 
 actually consumed by the two groups except that they had access to equal- 
 sized pastures of comparable feed. Stocking was at a rate above the average 
 maximum for the area. 
 
 Other information has demonstrated that animals on nutritionally deficient 
 diets consume less feed than when the ration is complete. From this we may 
 conclude that group 1 animals actually ate more forage during period I. The 
 fields, however, did not look noticeably different at the end of the period, for 
 feed disappears because of trampling, rodents, and weathering in any event. 
 The principal point is that in two equally stocked fields significant production 
 was induced in one case, actual weight was lost in the other, and the feed dis- 
 appeared in both. 
 
 As data (Wagnon, Griiilbert, and Hart, 1942) have shown, 300 to 600 pounds 
 of supplemental feeds given to calves, during periods comparable with period 
 I in this experiment, resulted in weight differences varying from 100 to 255 
 pounds between them and control animals (receiving no supplement) at the 
 end of the following grass season. In large-scale ranch operations, including 
 the supplementing of deficient range and of low-protein hay, about 100 pounds 
 greater weight has been attained with as low as 200 pounds of extra feed. 
 
 These combined results justify certain statements : In California 200 to 300 
 pounds of supplemental feed given to younger cattle to promote continuous 
 growth and efficient use of dry range or hay will very commonly result in 
 about 100 pounds of additional weight. Such feed will replace about 500 
 pounds of concentrates and 400 to 500 pounds of harvested roughage required 
 to make up this difference later in the feed lots. In other words, the time re- 
 quired for feed-lot finishing is reduced about half. 
 
 This over-all view of production from the calf to the final product, rather 
 than a view of isolated production phases, is important. It considers not only 
 the profit of the producer but also the maximum amount of human food that 
 can be produced at the state or national level with the total feed available. 
 In this experiment and others cited, a lifetime total of 1,400 to 1,738 pounds 
 of concentrates has resulted in grade-A long yearling* beef. Because of the 
 soil type, the relatively short period when the feed is nutritious, and the 
 acreage required per animal, this range must be considered a poor one from 
 the standpoint of finishing cattle. The amounts of concentrates cited, how- 
 ever, are not in excess of those required to finish in feed lots cattle of similar 
 age that have received no supplemental feed. 
 
 Judging from results, the total tonnage of beef produced from the feeds 
 available for beef cattle in California could be tremendously increased through 
 use of an increased proportion of the total for promoting continuous growth 
 during the 3 to 6 months of the year when the forage on most ranges is nu- 
 tritionally deficient or inadequate in quantity. The practice of allowing ani- 
 mals to gain and lose with the vagaries of climate and feed, although decreas- 
 ing, is still all too common. The lower efficiency of using the supplements and 
 concentrates only during a finishing period, either on range or in feed lots, 
 is shown by the fact that less total beef is produced with the same quantity 
 of feed. 
 
 The practicability of producing good-grade beef by a combination of sup- 
 
28 
 
 University of California — Experiment Station 
 
 TABLE 5 
 
 Carcass Data: Yield, Shrinkage, Yield of Wholesale Cuts, Carcass Values, and 
 
 Composition of Rib Cuts 
 
 Group 
 no. 
 
 Animal 
 no. 
 
 Carcass 
 
 yield, 
 
 per 
 
 cent* 
 
 Cooler 
 shrink- 
 age, 
 per 
 centf 
 
 Hind 
 quar- 
 ters, 
 per 
 centt 
 
 Fore 
 quar- 
 ters, 
 per 
 cent 
 
 Whole 
 
 round, 
 
 per 
 
 cent 
 
 Whole 
 loin, 
 per 
 cent 
 
 Prime 
 rib, 
 per 
 cent 
 
 Long 
 
 plate, 
 
 per 
 
 cent 
 
 Shin 
 and 
 shoul- 
 der, 
 per cent 
 
 Chuck, 
 per 
 cent 
 
 1 
 
 02 
 
 58.4 
 55.9 
 
 60.9 
 60.4 
 
 59.7 
 61.2 
 
 58.7 
 59.9 
 
 58.2 
 58.7 
 
 59.4 
 62.2 
 
 58.5 
 60.5 
 
 59 3 
 60.3 
 
 2.3 
 1.3 
 
 1.4 
 0.9 
 
 1.4 
 1.7 
 
 1.8 
 1.2 
 
 1.3 
 1.6 
 
 1.9 
 1.5 
 
 1.4 
 1.7 
 
 1.7 
 1.5 
 
 48.1 
 47.6 
 
 49.9 
 
 47.7 
 
 48.4 
 47.1 
 
 49 2 
 
 47.5 
 
 47.9 
 47.5 
 
 48.0 
 
 48.8 
 
 47.4 
 47.6 
 
 47.6 
 46.6 
 
 51.9 
 52.4 
 
 50 1 
 
 52.3 
 
 51.6 
 52.9 
 
 50.8 
 52.5 
 
 52.1 
 52.5 
 
 52.0 
 51.2 
 
 52.5 
 52.4 
 
 52 4 
 53.4 
 
 29.5 
 28.6 
 
 27.1 
 27.0 
 
 27.7 
 28.2 
 
 26.4 
 28.3 
 
 27.4 
 28.2 
 
 26.9 
 26.9 
 
 27.5 
 26.2 
 
 26.7 
 27.0 
 
 18.7 
 19.0 
 
 23.7 
 20.8 
 
 20.1 
 
 18.9 
 
 22.6 
 19.4 
 
 20 5 
 19.4 
 
 21.2 
 20.9 
 
 19.6 
 21.6 
 
 19.5 
 19.3 
 
 11.6 
 10.9 
 
 10 9 
 11.3 
 
 11.4 
 11.1 
 
 11.2 
 11.7 
 
 11.3 
 11.2 
 
 11.1 
 10.5 
 
 11.0 
 11.4 
 
 10 9 
 11.7 
 
 12.8 
 13.5 
 
 12 5 
 
 13 7 
 
 13.4 
 
 12.8 
 
 12.7 
 12.9 
 
 12.6 
 13.9 
 
 13.1 
 13.0 
 
 13.3 
 13.4 
 
 13.5 
 13.9 
 
 9.8 
 10.4 
 
 9.1 
 9.6 
 
 9.7 
 10.3 
 
 9.3 
 10 2 
 
 10.1 
 
 9.7 
 
 9.4 
 9.3 
 
 10.1 
 9.0 
 
 9.7 
 9.6 
 
 17.7 
 
 2 
 
 09 
 
 17.7 
 
 1 
 
 03 
 
 16.7 
 
 2 
 
 013 
 
 17.6 
 
 1 
 
 04 
 
 17.7 
 
 2 
 
 012 
 
 18.7 
 
 1 
 
 08 
 
 17.8 
 
 2 
 
 010 
 
 17.5 
 
 1 
 
 014 
 
 18.2 
 
 2 
 
 016 
 
 17.7 
 
 1 
 
 027 
 
 18.4 
 
 2 
 
 032 
 
 19.4 
 
 1 
 
 028 
 
 18.5 
 
 2 
 
 05 
 
 18.6 
 
 1 
 
 2 
 
 035 
 
 036 
 
 19.7 
 18.6 
 
 Group 1, average§ 
 
 Group 2, average§ 
 
 59.1 
 60.0 
 
 1.65 
 1.44 
 
 48.3 
 47.5 
 
 51.7 
 52.5 
 
 27.4 
 27.5 
 
 20.7 
 19.9 
 
 11.2 
 11.2 
 
 13 
 13.4 
 
 9.6 
 9.8 
 
 18.1 
 18.2 
 
 
 Animal 
 no. 
 
 Carcass 
 weight, 
 pounds 
 
 Carcass 
 grade 
 
 Total 
 value, i 
 dollars^ 
 
 Value per 
 cwt. due 
 to confor- 
 mation, 
 dollars|| 
 
 Composition of 12th and 13th rib cut 
 
 Group 
 no. 
 
 Fat, 
 per cent 
 
 Lean, 
 per cent 
 
 Bone, 
 per cent 
 
 Lean in 
 fat-free 
 
 cut, 
 per cent 
 
 1 
 
 2 
 
 1 
 
 2 
 
 02 
 
 09 
 
 03 
 
 013 
 
 514 
 
 391 
 
 569 
 541 
 
 612 
 520 
 
 640 
 
 488 
 
 541 
 
 478 
 
 573 
 
 588 
 
 559 
 
 584 
 
 578 
 579 
 
 Good 
 Commercial 
 
 Good 
 Good 
 
 Commercial 
 Commercial 
 
 Good 
 Commercial 
 
 Commercial 
 Commercial 
 
 Good 
 Good 
 
 Good 
 Good 
 
 Commercial 
 Good 
 
 118.22 
 
 81.84 
 
 132.52 
 124.48 
 
 128.28 
 108.78 
 
 148.35 
 102.43 
 
 113.83 
 100.04 
 
 132 31 
 135.18 
 
 128.18 
 134.79 
 
 120.69 
 132.59 
 
 23 00 
 22.93 
 
 23.29 
 23.01 
 
 22.99 
 22.95 
 
 23.18 
 22.86 
 
 23 08 
 22.94 
 
 23.09 
 22.99 
 
 22.93 
 23.08 
 
 22.87 
 22.90 
 
 28.9 
 24.1 
 
 38.8 
 35.2 
 
 28.5 
 21.9 
 
 34.5 
 28.0 
 
 30.3 
 32.8 
 
 35.5 
 33.6 
 
 32.8 
 35.8 
 
 32.0 
 35.5 
 
 56.0 
 
 57.6 
 
 48.8 
 48.6 
 
 56.6 
 61.8 
 
 51.6 
 55.7 
 
 53.2 
 52.5 
 
 51.6 
 51.6 
 
 50 
 
 49.5 
 
 51.9 
 52.5 
 
 15.1 
 18.3 
 
 12.4 
 
 16.2 
 
 14.9 
 16.3 
 
 13.9 
 
 16.3 
 
 16.5 
 14.7 
 
 12.9 
 14.8 
 
 17.2 
 14.7 
 
 16.1 
 12.0 
 
 78.8 
 75.9 
 
 79.7 
 75.1 
 
 1 
 2 
 
 1 
 
 04 
 
 012 
 
 08 
 
 79.2 
 79.1 
 
 78.7 
 
 2 
 
 010 
 
 77.4 
 
 1 
 
 014 
 
 76.4 
 
 2 
 
 016 
 
 78.4 
 
 1 
 
 027 
 
 75 
 
 2 
 
 032 
 
 77.6 
 
 1 
 
 028 
 
 74.5 
 
 2 
 
 05... 
 
 77.0 
 
 1 
 
 035 
 
 76.4 
 
 2 
 
 036...- 
 
 81.4 
 
 Group 1, average§ 
 
 573 
 521 
 
 
 127.79 
 115 02 
 
 23 05 
 22.95 
 
 32.7 
 30.9 
 
 52.4 
 53 7 
 
 14.9 
 15.4 
 
 77.9 
 
 Group 2. averaee§ 
 
 
 77.8 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 * Computed on the basis of selling weight and carcass weight after 7 days in cooler, 
 t Computed from warm dressed weight and carcass weight after 7 days in cooler. 
 % No ribs were left on the hindquarters. 
 
 § Italics indicate that the differences between group averages of basic data are statistically significant. 
 f Based on yield of wholesale cuts and price according to carcass grade. 
 
 || Based on yield of wholesale cuts and a standard price per pound for each cut. Variation, therefore, is caused 
 by difference in proportion of the various cuts. 
 
[Bul. 688] Importance of Continuous Growth in Beef Cattle 29 
 
 plemental and full-feeding on range is, moreover, demonstrated. This type 
 of production should have a real place, particularly when competition for feed 
 supply and labor is great : it produces more beef on the same feed by using it 
 more effectively at earlier age; and it saves large quantities of harvested, baled, 
 transported, and milled roughages necessary in feed-lot operations. 
 
 Growth and Development. — The average growth curves, figure 4, and the 
 individual growth curves, figures 5 to 8, show a high correlation between 
 changes in weight and changes in heart girth and round measurement. Skeletal 
 development, on the other hand, as represented by height, body length, and 
 head measurements, continued at a reduced rate in group 2 during the early 
 part of period I. This increase occurred when body substance was being used 
 to supplement the energy intake from the dry forage. When the animals were 
 very thin and the feed still poorer in quality and less abundant, skeletal 
 growth also came to a standstill. 
 
 At the end of period I, animals of group 2 lacked development. They ap- 
 peared to have relatively longer legs, slimmer and shallower bodies, and lighter 
 rear quarters, which gave them the appearance of poorer-bred cattle. Com- 
 parisons at this time are shown in the photographs taken December 30, 1941 
 (plates 1 to 7). 
 
 Although, by range standards, group 2 could not be considered weak at 
 the end of period I, the ease with which the hindquarters could be pushed 
 from side to side in the chute and the flabbiness of the shrunken thigh muscles 
 observed in the taking of round measurements were particularly striking. The 
 difference in the animals after supplements had been given for 5 weeks was 
 very impressive. The muscles felt firm and plump, with normal tonus; and a 
 conspicuous increase in measurement was shown. 
 
 Under the conditions of this experiment there was no conspicuous change 
 in the proportionate growth of length and width of heads. In McMeekan's 
 studies of swine (1940-1941) the animals were permitted to grow at reduced 
 rates for long periods and increased in bone length at the expense of bone 
 thickness ; heads became longer in relation to width. This is doubtless the ex- 
 planation for observed fineness of bone in cattle developed on poor ranges. 
 The earlier in life the privation occurs, the more striking is the result. Ham- 
 mond (1933) has shown that growth occurs in three overlapping phases, the 
 peak of bone growth preceding that of muscle, and muscle growth preceding 
 the peak of fat deposition. 
 
 Carcass Differences. — The difference in average carcass weight between 
 group 1 and group 2 shown in tables 4 and 5 was 52 pounds and is statistically 
 significant. In five of the eight pairs of animals there was a wide difference in 
 carcass weights. Carcass weights were equal in one pair, and group 2 animals 
 slightly exceeded their group 1 mates in two cases. Although the animals had 
 been carefully selected for uniformity of pairs, these and other data show that 
 there were genetic differences between them. Some were affected more than 
 others by privation, and there were evidently individual differences in ability 
 to respond to favorable environment. 
 
 Although in five out of eight pairs, group 1 animals were fatter as indicated 
 by the percentage fat in the rib cuts, and the group average was slightly higher 
 for group 1, the average difference was not statistically significant. In two of 
 
30 University of California — Experiment Station 
 
 three pairs in which carcass weight was equal or slightly greater in group 2 
 animals, the latter had the higher fat percentage. This situation might have 
 been expected from the results McMeekan (1940-1941) obtained with his low- 
 high group. To secure equal average group weights at the close of the experi- 
 ment, it would have been necessary to full-feed group 2 as was done and 
 allow group 1 to continue on grass alone from June to September, 1942. Since 
 group 1 was only in fleshy-feeder condition in June and no further net gain 
 could have been expected on grass alone, the average result would necessarily 
 have been similar to that in McMeekan's high-low and low-high groups. That 
 is, group 1 carcasses would have been high in lean compared with fat, whereas 
 group 2 would have averaged much fatter at the same average weight. 
 
 The small but statistically significant difference in hindquarter yield of 
 group 1 as compared with group 2, shown in tables 4 and 5, agrees with the 
 results of the Missouri and Cambridge experiments. Evidently, higher planes 
 of nutrition, particularly at the earlier ages, stimulate development of later- 
 maturing parts. Increasing fatness also tends to increase the proportion of 
 hindquarter weight. 
 
 Although the differences were not statistically significant, it is interesting 
 that the average shipping shrinkage of group 2 was less than that of group 1 
 in six of the eight pairs. Despite this and the fact that average fatness was less, 
 group 2 averaged slightly higher in dressing percentage. At the time of the 
 last measurements group 2 had slightly less paunch girth in relation to heart 
 girth than group 1. 
 
 Although group 1 averaged higher in per cent of fat and lower in lean and 
 bone of the rib cuts than group 2, the differences are not significant. There 
 was no difference in the proportion of lean to bone in the fat-free cuts (table 5.) . 
 Apparently whatever changes may have occurred during the period of priva- 
 tion suffered by group 2, the animals recovered under favorable conditions 
 and ultimately had relative amounts of bone and lean comparable with group 
 1. The differences noted in the proportion of lean and bone in the whole cut 
 were caused by fat variation. 
 
 The carcass value per hundredweight was computed by multiplying the 
 percentage of each cut by the following prices per hundredweight : 
 
 Good Commercial 
 
 grade grade 
 
 Whole rounds $24.00 $22.00 
 
 Whole loins ; 29.00 25.00 
 
 Prime rib 25.00 23.00 
 
 Long plate 14.50 14.00 
 
 Shin and shoulder 22.50 20.50 
 
 Chuck 20.00 19.00 
 
 Average $23.00 $21.00 
 
 The averages were the ceiling prices for good and commercial whole carcasses 
 at the time of slaughter. The proportionate prices of cuts are believed to be 
 reasonably well in line with general practice, though they vary considerably, 
 depending on demand and on method of cutting. 
 
 Total value of each carcass was derived by multiplying average carcass 
 
[Bul. 688] Importance of Continuous Growth in Beef Cattle 
 
 31 
 
 value per hundredweight by the carcass weight and thus includes variations 
 due both to grade and to conformation. 
 
 Table 6 presents data on some of the more important items that contribute 
 to the value of the animals and carcasses. The animals are listed without re- 
 spect to group and in order of degree of fatness as indicated by analysis of 
 
 the rib cut. 
 
 TABLE 6 
 
 Comparison of Various Marketing, Slaughter, and Carcass Data 
 (Arranged in order of increasing fat content of rib cuts) 
 
 Animal 
 no. 
 
 Live 
 animal 
 grade* 
 
 Official 
 
 U. S. carcass 
 
 grade 
 
 Packer 
 
 carcass 
 
 grade 
 
 Live 
 
 animal 
 price per 
 hundred- 
 weight 
 
 Percent 
 
 fat in 
 
 rib cut 
 
 Carcass 
 value 
 due to 
 grade 
 and con- 
 forma- 
 tion 
 per cwt.f 
 
 Carcass 
 value 
 due to 
 confor- 
 mation 
 alone 
 per cwt.f. 
 
 Dress- 
 ing, 
 per cent 
 
 012 
 
 Commercial 
 
 Commercial 
 
 Commercial 
 
 $12.50 
 
 21.9 
 
 $20.92 
 
 $22.92 
 
 61.2 
 
 09 
 
 Commercial-f- 
 
 Commercial 
 
 Commercial 
 
 12.50 
 
 24.1 
 
 20.93 
 
 22.93 
 
 55.9 
 
 010 
 
 Commercial+ 
 
 Commercial 
 
 Commercial 
 
 13.50 
 
 28.0 
 
 20.99 
 
 22.86 
 
 59.9 
 
 04 
 
 Good 
 
 Commercial 
 
 Good 
 
 14.00 
 
 28.5 
 
 20.96 
 
 22.99 
 
 59.7 
 
 02 
 
 Commercial-|- 
 
 Good 
 
 Good 
 
 13.50 
 
 28.9 
 
 23.00 
 
 23.00 
 
 58.4 
 
 014 
 
 Commercial+ 
 
 Commercial 
 
 Good 
 
 14.00 
 
 30.3 
 
 21.04 
 
 23.08 
 
 58.2 
 
 035 
 
 Good 
 
 Commercial 
 
 Good 
 
 14.00 
 
 32.0 
 
 20.88 
 
 22.87 
 
 59.3 
 
 028 
 
 Commercial-f- 
 
 Good 
 
 Good 
 
 13.50 
 
 32.8 
 
 22.93 
 
 22.93 
 
 58.5 
 
 016 
 
 Good- 
 
 Commercial 
 
 Good 
 
 13.50 
 
 32.8 
 
 20.93 
 
 22.94 
 
 58.7 
 
 032 
 
 Good- 
 
 Good 
 
 Good 
 
 14.00 
 
 33.6 
 
 22.99 
 
 22.99 
 
 62.2 
 
 08 
 
 Good+ 
 
 Good 
 
 Good 
 
 14.00 
 
 34.5 
 
 23.18 
 
 23.18 
 
 58.7 
 
 013 
 
 Good 
 
 Good 
 
 Good 
 
 14.00 
 
 35.2 
 
 23.01 
 
 23.01 
 
 60.4 
 
 036 
 
 Good 
 
 Good 
 
 Good 
 
 14.00 
 
 35.5 
 
 22.90 
 
 22.90 
 
 60.3 
 
 027 
 
 Good 
 
 Good 
 
 Good 
 
 14.00 
 
 35.5 
 
 23.09 
 
 23 09 
 
 59.4 
 
 05 
 
 Good 
 
 Good 
 
 Good 
 
 14.00 
 
 35.8 
 
 23.08 
 
 23.08 
 
 60.5 
 
 03 
 
 Good+ 
 
 Good 
 
 Good 
 
 $14.00 
 
 38.8 
 
 $23 . 29 
 
 $23 . 29 
 
 60.9 
 
 * The signs + and — indicate top and low end of grade respectively, 
 t See text for wholesale cut prices. 
 
 t Prices for good grade were used throughout in these calculations. Value per hundredweight variation is 
 therefore due solely to differences in proportion of various cuts. 
 
 There was perfect agreement in the grading of the live animals, the buying 
 price, and the carcass grade in the first three animals (fat content 28 per cent 
 and under) and in the last seven (fat content 33.6 to 38.8 per cent) . Animals 
 04 to 016 inclusive ranged between 28.5 and 32.8 per cent fat in the rib cut, 
 were borderline between good and commercial, and caused considerable varia- 
 tion in judgment. Carcass value per hundredweight due to both grade and 
 conformation is shown, and also variation due to conformation alone. For 
 these latter calculations the price for good grade was used throughout and 
 was applied to the percentage yield of cuts of each carcass. The maximum 
 difference in value due to conformation (proportion of wholesale cuts) was 
 43 cents per hundredweight, a difference of 1.9 per cent. Since all these animals 
 were considered to be within the limits of the range of one grade as feeders, 
 no great difference might be expected. 
 
 Largely because of higher yield of hindquarter in group 1, the average value 
 due to conformation was slightly higher in this group (table 5). 
 
 Dressing percentage in general tended to increase with the fat content. Size 
 
32 University of California — Experiment Station 
 
 of middle and amount of fill were also important factors causing variation. 
 No. 012, the very nervous steer, had little fill and second highest carcass 
 yield, although he was the least fat. 
 
 Lush (1926) and workers in the U. S. Department of Agriculture Bureau 
 of Animal Industry (Black and co-workers, 1940) found high correlation 
 between the percentage of fat in the edible portion of rib cuts and the per- 
 centage of fat in the entire carcass ; they developed formulas for estimating 
 the latter from the former. Total carcass fat content in this experiment was 
 calculated by means of the Bureau of Animal Industry equation : The per- 
 centage of fat (ether extract) in the edible portion of the carcass is 0.738 
 times the percentage of fat (ether extract) in the edible portion of the 9th, 
 10th, and 11th rib cut plus 3.56 per cent. 
 
 According to these calculations the carcasses that all graders agreed were 
 commercial (nos. 012 to 010 inclusive, table 6) varied from 22.9 to 28.2 per 
 cent fat in the edible portion of the carcasses ; those that were borderline, with 
 incomplete agreement (nos. 04 to 016 inclusive), varied from 29.3 to 31.3 per 
 cent ; those that all graders regarded as good grade (nos. 032 to 03 inclusive) 
 varied from 32.7 to 36.2 per cent fat. 
 
 No data are available to show that the 12th and 13th rib cuts used in the 
 present experiment are strictly comparable in composition with the 9th, 10th, 
 and 11th rib cuts, upon which the equation above is based. Since the loin nor- 
 mally contains more fat than the prime ribs, one might expect the rib cuts 
 nearest the loin to contain somewhat more fat. Black and his co-workers (1940) 
 estimated the fat in carcasses according to this formula. They obtained 
 average values of 23.94 to 31.09 per cent for groups of steers varying in carcass 
 grade from average commercial to average good. Chatfield (1926) estimated 
 that commercial carcasses varied between 18 and 25 per cent fat in the edible 
 portion, and good-grade carcasses from 25 to 35 per cent. Judging from these 
 results, further data are required before one can rely on the fat content of the 
 12th and 13th rib cuts for estimating fat in the entire carcass. These cuts were 
 used in the present work because of the Pacific Coast practice of leaving all 
 ribs on the f orequarter and because of the convenience and economy of using 
 the first two-rib cut. 
 
 SUMMARY AND CONCLUSIONS 
 
 The experiment was designed to obtain data on the effectiveness of supple- 
 mental feed supplied at different periods of the year and at different stages 
 of development of the animals — factors that influenced the shape of their 
 growth curves. Data on costs, gains, and the carcass quality were obtained. 
 
 The sixteen steers to be finished as yearlings were selected from the San 
 Joaquin Experiment Range herd at weaning time (July 1, 1941) and were 
 divided into eight closely matched pairs, distributed equally into groups 1 
 and 2. The time interval of slightly over 14 months (July, 1941, to September, 
 1942) was divided into three periods: first, the dry-feed period from July to 
 January ; second, the green-feed period from January to June; third, a finish- 
 ing period from June to September 7, when both groups were full-fed con- 
 centrates on dry forage. 
 
 The main difference in management consisted in feeding group 1 steers con- 
 
[Bul. 688] Importance of Continuous Growth in Beef Cattle 33 
 
 centrate supplements through period I so that they gained about 1 pound 
 daily, whereas group 2 (in accordance with common practice) subsisted on 
 range feed alone, and lost weight. In period II, group 1 received range feed 
 only and, after a short period when green forage was scant and high in mois- 
 ture, continued to gain. Group 2, on the other hand, now received concentrate 
 supplements with range feed and made greater gains. As is well recognized, 
 steers that maintain or lose weight in the dry -feed or winter season will gain 
 faster during the following green-feed season than comparable groups that 
 have made continuous gain induced by supplemental feeding. In this experi- 
 ment, feeding supplements to previously deprived animals in group 2 enhanced 
 their gain during period II. Group 1 gained an average of 182 pounds during 
 this period and at its close weighed 860 pounds, as compared with a gain of 304 
 pounds and an average weight of 765 pounds for steers of group 2. In period 
 III both groups were full-fed concentrates on the range at the rate of ap- 
 proximately 1 pound per 100 pounds live weight. 
 
 As a result of difference in management practice, group 1 returned $17.51 
 more per head, whereas the supplemented feed cost was only $1.40 greater, 
 only 70 pounds more concentrates having been consumed by them than by 
 group 2. This result was due to an average of 108 pounds greater live weight, 
 52 pounds greater carcass weight, and a somewhat higher selling price for 
 group 1. 
 
 During the 14-month period, changes in body size and proportions were 
 recorded by means of weights, body measurements, and photographs. Data on 
 grades and proportions of wholesale cuts for each carcass showed on the aver- 
 age that group 1 animals had the advantage. 
 
 Their greater efficiency was due to comparatively small daily allowances of 
 supplement. These allowances permitted efficient utilization of the nutrition- 
 ally deficient dry forage in period I, thereby promoting continuous growth 
 when the stimulus was greatest and decreasing the proportion of feed utilized 
 for maintenance. According to these and other data, 200 to 300 pounds of 
 supplemental feed used at earlier ages will in California commonly result in 
 100 pounds of additional weight and in a higher selling price for feeders. It 
 will, furthermore, save about 500 pounds of concentrates and 400 to 500 
 pounds of harvested roughages necessary to make up this difference later in 
 feed lots. Thus, in California, advantage would be derived if feeds available 
 for beef cattle were used in greater proportion to supplement range, and 
 relatively less feed would then be required for finishing in feed lot. As the 
 data also demonstrate, a combination of supplemental feeding for continuous 
 growth, followed by a finishing period on range with concentrates full-fed, 
 can produce grade-A long yearling beef. This saves the labor involved in the 
 harvesting, baling, transporting, and milling of roughages — a consideration 
 particularly important in wartime. 
 
 Many better California ranges will yield superior finish with less concen- 
 trates than the San Joaquin Experimental Range. 
 
 During their period of privation, group 2 animals had relatively longer legs, 
 slimmer shallower bodies, and lighter rear quarters with finer bone, which gave 
 them the appearance of poorer-bred animals. Skeletal growth continued dur- 
 ing the early part of the period, but practically ceased toward the end. 
 
34 University of California — Experiment Station 
 
 At the conclusion of the experiment there was no significant difference in 
 average fatness of the two groups. Group 1 yielded relatively more hind- 
 quarter than group 2. These results agree with swine and sheep data cited, 
 which show that a high plane of nutrition early in life followed by a lower 
 plane results in carcasses higher in lean and lower in fat than when the 
 reverse occurs, even though the same final weight at the same age is obtained. 
 The data support the evidence that high planes of nutrition speed up the 
 development of thickness growth generally, especially in later-maturing parts 
 such as loin and hindquarter. 
 
 According to analysis of rib cuts from each carcass, on a fat-free basis, there 
 was no difference in proportion of lean to bone between the two groups. 
 
 From the standpoint of total feed required to produce a unit of product, 
 greatest efficiency is obtained from a high plane of nutrition, with continuous 
 growth and development. The degree of approach to the ideal that may be 
 made under specific conditions depends upon the relative costs of different 
 phases of production — for example, cost of summer gain on range compared 
 with winter gain on hay. Particularly when maximum production is being 
 stressed, one should consider the birth-to-slaughter feed requirement and the 
 feed used at the stages and in the amounts that will yield greatest over-all 
 efficiency. When this broad view is taken, there is a high correlation between 
 biological efficiency and dollars-and-cents economy. 
 
 The principles and objectives brought out in this experiment may be realized 
 in ways other than the feeding of concentrate supplements. To secure con- 
 tinuous growth and development one may, for example, make coordinated use 
 of native forage and irrigated pasture; or one may improve the quality of 
 hay by including legumes and by cutting and curing the hay in a manner 
 that will preserve its nutritive value ; or one may adopt better methods of 
 feeding. Any consideration of efficiency of beef production must begin with 
 the cow herd, the percentage calf crop, and the weaning weight. Adaptation 
 of creep-feeding practices to special conditions is another possible way of 
 increasing low-cost gain. 
 
 The experiment reported was designed primarily to illustrate a principle 
 rather than to indicate an exact practice. A six-year program is under way at 
 the San Joaquin Experimental Range to obtain detailed information on the 
 most practical methods for range finishing of long-yearling steers. This in- 
 volves the amount of feed and the most efficient rate of gain from weaning until 
 the next grass season ; the question of feeding concentrates during the green- 
 forage season or of full-feeding at the end of this season ; and, finally, the best 
 combination of practices for the three phases of this type of production pro- 
 gram. Each livestock producer should make such adaptations of these prin- 
 ciples as his individual situation makes practical. 
 
[Bul. 688] Importance of Continuous Growth in Beep Cattle 35 
 
 LITERATURE CITED 
 
 Black, W. H., J. R. Quesenberry, and A. L. Baker. 
 
 1939. Wintering steers on different planes of nutrition from weaning to 2^ years 
 of age. U. S. Dept. Agr. Tech. Bul. 667:1-20. 
 
 Black, W. H., R. L. Hester, L. B. Burk, L. M. Alexander, and C. V. Wilson. 
 
 1940. Beef production and quality as affected by methods of feeding supplements to 
 steers on grass in the Appalachian Region. U. S. Dept. Agr. Tech. Bul. 717:1-32. 
 7 figs. 
 
 Chatfield, C. 
 
 1926. Proximate composition of beef. U. S. Dept. Agr. Dept. Cir. 389:1-18. 
 Gregory, P. W. 
 
 1933. The nature of size factors in domestic breeds of cattle. Genetics 18:221-49. 
 Guilbert, H. R., L. W. Fluharty, and V. M. Shepard. 
 
 1943. California beef production data. California Agr. Exp. Sta. Lithoprint Leaflet. 6 p. 
 Guilbert, H. R., and H. Goss. 
 
 1944. Digestibility of range forages and flax hulls. California Agr. Exp. Sta. Bul. 
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 Hammond, J. 
 
 1933. How science can help improve the nation's food supply. Soc. Chem. Indus. Jour. 
 
 52:637-40. 
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 p. 88.) Longmans, Green and Co., New York, N. Y. 
 Hutchison, C. B., and E. I. Kotok. 
 
 1942. The San Joaquin Experimental Range. California Agr. Exp. Sta. Bul. 663:1-145. 
 Lush, J. L. 
 
 1926. Practical methods of estimating the proportions of fat and bone in cattle 
 slaughtered in commercial packing plants. Jour. Agr. Res. 32:727-55. 
 
 McMeekan, C. P. 
 
 1940-1941. Growth and development in the pig, with special reference to carcass 
 
 quality characters. Jour. Agr. Sci. 30:276-337; 31:1-161. 
 Moulton, C. R., P. F. Trowbridge, and L. D. Haigh. 
 
 1921. Studies in animal nutrition. I. Changes in form and weight on different planes 
 
 of nutrition. Missouri Agr. Exp. Sta. Res. Bul. 43:1-111. 30 figs. 
 1922a. Studies in animal nutrition. II. Changes in proportions of carcass and offal on 
 
 different planes of nutrition. Missouri Agr. Exp. Sta. Res. Bul. 54:1-76. 28 figs. 
 1922b. Studies in animal nutrition. III. Changes in chemical composition on different 
 
 planes of nutrition. Missouri Agr. Exp. Sta. Res. Bul. 55 : 1-88. 20 figs. 
 
 Trowbridge, P. F., C. R. Moulton, and L. D. Haigh. 
 
 1915. The maintenance requirement of cattle. Missouri Agr. Exp. Sta. Res. Bul. 18: 
 1-62. 17 figs. 
 
 1918. Effect of limited food on growth of beef animals. Missouri Agr. Exp. Sta. Res. 
 Bul. 28:1-129. 23 figs. 
 
 1919. Composition of the beef animal and energy cost of fattening. Missouri Agr. 
 Exp. Sta. Res. Bul. 30:1-106. 25 figs. 
 
 Verges, J. B. 
 
 1936. The effect of nutrition on the carcass quality of Suffolk cross lambs. Suffolk 
 Sheep. Soc. Yearbook, Ipswich. (Original not seen; cited by Hammond, 1940.) 
 Wagnon, K. A., H. R. Guilbert, and G. H. Hart. 
 
 1942. Experimental Herd Management. In: Hutchison, C. B., and E. I. Kotok. The 
 San Joaquin Experimental Range. California Agr. Exp. Sta. Bul. 663:50-82. 
 
 Watson, D. M. S. 
 
 1943. Beef cattle in peace and war. Empire Jour. Exp. Agr. 11:191-228. 
 
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